Fish_v2_L_Ha_SHO__crty2_14__tpzSN_3_0__tf16_WCS_Annotated

NGC 896, IC 1795, Fishhead Nebula, Lynds Catalogue LBN 645. L(Ha)SHO narrow band composite, Foraxx Palette

 

Image is NGC 896, the Fishhead Nebula in L(Ha)SHO narrow band. Image and an annotated version. The image is rendered with the Foraxx Palette Utility script in PixInsight. Apart from a little cosmetic tweaking at the end, the product is all Foraxx.

 

NGC 896 is an emission nebula of glowing gas and darker dust lanes situated in the Perseus Arm in the northern sky. It forms a small part of the larger Heart nebula (which is several degrees square).

 

Details:

Fishhead Nebula, NGC 896, IC 1795, LBN 645

Distance: 6,000 lyrs

Diameter: 70 lyrs

Angle subtended: 40'x15'

Constellation: Cassiopeia

 

Data taken in Astronomik narrowband filters: Ha (656nm), Sii (672nm) and Oiii (501nm). Total exposure time 15 hrs.

 

Ha 1x1 bin - 22x 600s = 3.7hrs, 03-04 September, seeing 2.6", scope West side, prime focus

Sii 1x1 bin - 33x 600s = 5.5hrs, 04-05 September, seeing 1.8", scope West side, prime focus

Oiii 1x1 bin - 35x 600s = 5.8 hrs, 05-06 September, seeing 1.2", scope West side, prime focus

 

Master lights:

FWHM (pxl)pre BXTpost BXT

Ha2.4401.476

Sii2.9421.666

Oiii3.1632.524

 

-----

Plate solver:

Resolution ............... 1.247 arcsec/px

Focal distance ........... 750.71 mm

Pixel size ............... 4.54 um

Field of view ............ 56' 1.8" x 43' 58.3"

Image center ............. RA: 2 28 13.183 Dec: +62 01 33.70

Image bounds:

top-left .............. RA: 2 24 25.590 Dec: +62 25 19.95

top-right ............. RA: 2 32 27.835 Dec: +62 21 12.52

bottom-left ........... RA: 2 24 04.018 Dec: +61 41 26.22

bottom-right .......... RA: 2 31 54.880 Dec: +61 37 24.65

-----

Rig:

Imaging scope: SW Startravel 150mm F5 Refractor, Baader Diamond Track, (2.5x Celestron Luminos 2inch imaging barlow), Atik 460EX mono

 

Guide scope: SW Evostar 90mm F10, with guiding XY stage, ZWO 120MM camera

 

Guiding: 2 stage PHD: high frequency guide scope (mount tracking) and low frequency OAG image train guiding (guidescope flex)

 

Mount: Home made German Equatorial pillow block mount, permanently rooftop mounted. Spring loaded DEC axis gearing.

 

Other gadgets: ST4 based anti vibration shutter, ST4 based PEC

-----

Processing Lights:

PixInsight: Lights, Darks, Flats, Biases: master dark/dark library-> masterbias-> superbias-> calibrated flats-> master flat-> calibrated lights-> cosmetic correction-> aligned lights-> master light-> BXT

 

PixInsight: Master BXT lights-> crop-> linfit-> final master lights

 

PixInsight: final master lights->StarNet2 starless-> LRGB Channel Combination (Ha, SHO)-> export xisf starless master.

 

GradXpert Gradient removal:->import starless xisf-> GXPT(20pc,3sg)-> export xisf, fits

 

Affinity Photo 32 bit image processing:-> import LSHO gxpt starless fits-> accept default stretch-> curves-> lvl(master)-> Topaz Denoise(LL, 22, 31)-> Tpzdn(ST,15,13)-> export tiff 16 bit

 

PixInsight: import tiff16-> channel separation-> Foraxx Palette Utility Script-> export Foraxx tiff 16

 

Affinity Photo final tart ups:-> import Foraxx tiff 16-> cvs-> scol (50%blend)-> 2x clarity, B&C tweaks->Tpzdn(LL,3,0)-> paste in star mask layer, blend mode 'screen', B&C, White Balance adjust.

 

-----

Processing Star Mask:

PixInsight: final master lights-> RGB Channel Combination (SHO)-> export xisf

 

GradXpert Gradient removal:->import xisf-> GXPT(20pc,3sg)-> export xisf

 

PixInsight: import SHO gxpt master-> StarNet2 star mask-> SCNR(Mg, 0.57)-> export fits starmask

 

Affinity Photo 32 bit image processing:-> import SHO gxpt starmask fits-> accept default stretch-> vibrance-> Sii master light star mask overlay (B&C adj, blend mode 'luminosity')-> paste Star Mask layer on top of starless final (blend mode 'screen').

 

-----

Done